Products from rocks

Question 1

What is limestone?

Answer 1

Mainly calcium carbonate (CaCO3)

Question 2

What happens when limestone is heated?

Answer 2

It thermally decomposes, creating calcium oxide and carbon dioxide ( CaO + CO2)

Question 3

What happens when limestone reacts with acid?

Answer 3

It makes calcium salt, carbon dioxide and water (CaSO4 + CO2 + H2O)

Question 4

What happens when you add calcium hydroxide to water?

Answer 4

You get calcium hydroxide - which is an alkali and can be used to neutralise acid soil

Question 5

What can limewater be used for?

Answer 5

Checking if carbon dioxide is present - it will turn cloudy

Question 6

What are the advantages and disadvantages of limestone?

Answer 6

Limestone builds roads
Can neutralise acids
Mining it brings jobs
Cheaper than most rocks

Mining makes noise and dust
Causes visual pollution
Needs to be transported away - carbon footprint

Question 7

What is a metal ore?

Answer 7

A rock with enough metal in to be worth extracting

Question 8

How can metals be extracted from rocks?

Answer 8

Chemically - by reduction or electrolysis

Question 9

How do you know whether to use electrolysis or reduction to extract a metal?

Answer 9

If it’s below carbon on the reactivity scale, use carbon with reduction to extract it

If it’s above, use electrolysis

Question 10

How does electrolysis work?

Answer 10

An electrolyte contains the dissolved metal

An electric charge flows through it, and two rods become positive and negative (anode and cathode)
The electric charge flows through the electrolyte as it has free ions

The electrons are attracted to the anode and the metal ions are attracted to the cathode
(They then turn back into molecules as they join with the electrons that make the cathode negative)

Question 11

How is copper extracted using displacement?

Answer 11

A more reactive metal (iron) is placed into a solution of dissolved copper

Iron is cheaper than copper, so iron is used to displace. The iron kicks copper out and replaces it in the solution, so copper metal is formed

Question 12

What are experimental ways to extract small amounts of copper?

Answer 12

Bioleaching uses bacteria to extract copper, the bacteria gets energy from the bond between copper and sulphur, separating the copper

Question 13

What are the advantages and disadvantages of extracting metals?

Answer 13

Useful products can be made
Provides local people with jobs - brings money into the area
Therefore healthcare and transport improved

Noise pollution
Loss of habitats
Dangerous mine shafts

Question 14

What are the properties of a transition metal?

Answer 14

Metals are strong and can be bent

Good conductors (heat and electricity)

Shiny

Question 15

What are the specific properties of copper, aluminium and titanium?

Answer 15

Copper - good conductor of electricity, hard and strong but can bend, doesn’t react with water

Aluminium - low density, corrosion resistant, weak

Titanium - same as aluminium but strong

Question 16

What is metal fatigue?

Answer 16

A metal can collapse when put under stress over time and could be very dangerous

Question 17

What is an alloy?

Answer 17

Mixing two metals together (or a metal with a non-metal)

Question 18

What is steel?

Answer 18

An alloy, made from iron and carbon

Question 19

Why are alloys harder than metals?

Answer 19

The mismatch of particles mean different sized particles, meaning it’s harder to slide over each other

Question 20

What’s a mixture?

Answer 20

A mixture of two or more elements or compounds that aren’t chemically joined together

Question 21

How does fractional distillation of crude oil work?

Answer 21

The mixture is put into a heated tube.
The liquid is siphoned off straight away
The rest of the mixture is evaporated and cools on different levels of the tube due to their boiling points
Therefore the crude oil is separated out and siphoned off due to their boiling points

Question 22

What is the formula for alkanes?

Answer 22

Cn H2n+2

Question 23

What is Monkeys Eat Peanut Butter?

Answer 23

Methane
Ethane
Propane
Butane

Question 24

What are the properties of a short polymer?

Answer 24

Runny
Volatile (low boiling point)
More flammable

Question 25

What are the properties of a long polymer?

Answer 25

Viscous
High boiling points
Less flammable

Question 26

What is complete combustion?

Answer 26

When all the oxygen is burnt - releasing water vapour and carbon dioxide

Question 27

What is incomplete combustion?

Answer 27

When there’s a lack of oxygen - leading to carbon monoxide or carbon (soot)

Question 28

How does acid rain form?

Answer 28

Sulphur dioxide mixes with the clouds to form sulphuric acid, which falls as acid rain

Question 29

What are the consequences of acid rain?

Answer 29

Causes lakes and habitats to become acidic, poisoning animals and plants

Kills trees and damages buildings

Question 30

How do you prevent sulphur entering the atmosphere?

Answer 30

It can be removed from fuels before they’re burnt, but this is expensive

Petrol and diesel are being replaced by low sulphur ones

Question 31

What is the difference between global warming and the greenhouse effect?

Answer 31

The greenhouse effect is good, it keeps our planet warm and protects us from the sun

Global warming is an excess of greenhouse gases and is bad

Question 32

What is global dimming?

Answer 32

Particles in the atmosphere are becoming more frequent and they reflect light back into space

Question 33

What are examples of alternative fuels?

Answer 33

Ethanol - carbon neutral (as the plant making it has taken carbon dioxide) but engines need to be converted

Biodiesel - Carbon neutral, but expensive to make

Hydrogen gas - clean but hard to store and expensive to get